I am using 'com.android.support.constraint:constraint-layout:2.0.0-alpha5'.
I have a fragment using MotionLayout inside an activity that also carries a BottomNavigationView inside a CoordinatorLayout with a custom behaviour allowing to show and hide when the content is scrolled.
With all fragments, where there is no MotionLayout, this behaviour works perfectly. Only with the MotionLayout, which has a NestedScrollView as a child, and makes use of an onSwipe transition, this swipe seems to be consumed, and does not arrive at the activity's coordinator layout.
Is this a current limitation of how MotionLayout works, and is it possible to extend it to support my use case?
Related
I got a parent layout, activity_main.xml, with multiple views inside it, one of which is the RecyclerView view.
Within the recycler view, there are buttons that, once the user deals with them, I would like things to happen in the parent layout that is activity_main.xml.
For example, if I press a button on a ViewHolder item inside the child RecyclerView, in some cases, I would like changes to happen in the parent activity_main.xml layout.
However, my problem is that I don't know how to allow for this communication to happen.
What might be the best practices for such cases?
You need to create an interface callback or use a higher-order function.
This Stack Overflow answer is an example of an interface callback:
How to access component of MainActivity in recycler view to make onclick listener?.
Kotlin Lambda Functions For RecyclerView Adapter Callbacks in Android is for higher-order functions.
I've read the documentation of this attribute:
An additional flag to be used with 'snap'. If set, the view will be snapped to its top and bottom margins, as opposed to the edges of the view itself.
https://developer.android.com/reference/com/google/android/material/appbar/AppBarLayout.LayoutParams.html#scroll_flag_snap
But I can't observe any actual effect in my app. What margin are they talking about? Every margin on the CollapsingToolbarLayout (on which this attribute is set) completely destroys the layout.
Not sure if it's useful yet, but here is the difference:)
If you pass snap as scroll flag, then it will move your view (in my case this search bar, it's linearLayout) to it's edge NOT INCLUDING the margin_layout
Then I've tried snap|snapMargin and it moved with the margin
P.S. No idea why snapMargin doesn't work without snap ¯\_(ツ)_/¯
This attribute is responsible for a scrolling behavior of AppBarLayout and its children. You can apply it directly to AppBarLayout or on the inside views, in the xml layout of your AppCompatActivity. It has to be an instance of AppCompatActivity if you want to use AppBar features. Also, the design library must be included in Gradle dependencies, like so: implementation 'com.android.support:design:26.1.0'
Please refer this link:-[https://medium.com/#tonia.tkachuk/appbarlayout-scroll-behavior-with-layout-scrollflags-2eec41b4366b][1]
Respected Android Programmer,
I am facing the one major problem is that nested scroll view not get disable. Here I am using RecylerView inside the Nested ScrollView.
Actually I am using the so many fragments in one Activity so when default recylerview loaded the listing user the Nested Scrolview now i have to click on floating button i have to hide the that fragment with with trance parent layout or frame layout. Its done but now problem is that when i use all function of recycler like
NestedScrollView mScrollView;
mScrollView.setNestedScrollingEnabled(false);
Not working may i know the reason.
Best
Romesh Chand
I want to add a new View to a Layout dynamically by layout.addView(view) method. The new View is not supposed to be visible, but I want it's Display List to be created so it doesn't have to redraw (call onDraw method) itself when I decide to show it (by animation, for example fade in).
I run this code:
customView = new CustomView(this.getContext());
customView .setAlpha(0.0f);
this.addView(customView ); // 'this' is RelativeLayout instance in this case
onDraw method gets called for customView and everything is fine. However, when I change anything in my layout (push a button, scroll, anything that invalidates layout), the onDraw method for my customView is called second time. After that, it isn't called any more if I don't invalidate my customView (correct behaviour).
I don't know why Android behaves this way. I want it to create customView, call onDraw, create a Display List for it, and not call onDraw any more until I invalidate my view. To sum up, onDraw is supposed to be called once.
And it has nothing to do with initial invisibility of customView, if alpha is set to 0.5f, behaviour is the same.
My question is, how to make Android call onDraw only once?
And if Android really has to call onDraw twice, then what should I do to enforce it to do it in some code right after this.addView(view); without setting up any timers because THAT would be totally ugly.
The behavior you are describing is ok and is a part of the android framework for view object -
Drawing
Drawing is handled by walking the tree and rendering each view that
intersects the invalid region. Because the tree is traversed in-order,
this means that parents will draw before (i.e., behind) their
children, with siblings drawn in the order they appear in the tree. If
you set a background drawable for a View, then the View will draw it
for you before calling back to its onDraw() method. Note that the
framework will not draw views that are not in the invalid region. To
force a view to draw, call invalidate()
(Taken from the official google android API docs).
Meaning your custom view is contained by the same view that contains the button\scrollbar etc. If you don't want it to be rendered everytime the onDraw method is called for the subtree your view resides in you can set the view's boolean flag to false - use setWillNotDraw() to do that. (you should place it on the activity's onCreate in order to render the view set this flag to false (which is also the default) and use invalidate() whenever you want to render the view).You can read the official google docs for further information.
i am new to GWT and GWTP and the question sounds stupid.. Can I make an abstract PresenterWidget or similiar?
Like in normal Java extending the "class" and reuse / extend the logic. But not only the class, the whole thing of View and Presenter. I try to explain my initial situation and maybe you have another idea.
The image hopefully helps to explain it. The "Main-Tab" and every other tab consists of a collection of views which have the same base structure and the same logic.
the base structure consists of
border around EVERYTHING
an image (the wwitch)
a title
a textarea
a PresenterWidget which is added to a contentSlot of the parent (the menu left)
and below the base are view specific components like buttons, text or any other widget. So a main part of the view with logic is repeading. If the switch is "toggled" the view is hidden (the textarea and any childs / view specific components) like the lowest view in the picture. Furthermore the PresenterWidget left changes the color.
The logic is working, but now I am searching a proper way to solve this without repeading code and the possibility to add child elements which are hidden as well by toggling the switch. Can I add to a PresenterWidget child widgets and define where there should be added? like: Even if this is possible, it feels a bit inconvenient.
Thanks in advance.
I just want to post the solution:
I have now a simple Composite (KPICommonView) for the switch, title and the description. It got another FlowPanel below the description, where the specific components will be added later. For this the Composite implements "HasWidgets" and overrides the "add(Widget w)"-method which is called by UiBinder if the Widget is added and has child elements.
<own:KPICommonView title="First Header" description="I am a happy description :)" anchorToken="{nameAnchors.getFirst}">
<g:Label>child component</g:Label>
</own:KPICommonView>
I am not sure if I do a PresenterWidget for every segment and every PresenterWidget has one of the KPICommonView added, or if I do one normal Presenter which adds more than one of the CommonViews.
The CommonView furhter creates the PresenterWidget for the menu item on the side. It gets the attributes from the constructor (anchorToken, title) and adds it to the slot (which happens ugly, because the View has hard coded the parent saved to call "addInSlot()". The repeading code for the switch is handled by the KPICommonView.